The USPS lost $200,000,000 over the holiday season

The results also reflect continued erosion in the delivery of first-class mail as well as expensive mandates for pre-funding of its retiree health care obligations.

The post office's report shows earnings of more than $1.4 billion between October and December 2016. But when effects of a $1.7 billion change in workers' compensation liability due to fluctuating interest rates are excluded, the service says it lost money overall.

Operating income came to $522 million, down from $1.3 billion in the previous year.

The post office said election-related mail yielded $226 million in revenue. (That's a jump from $42 million for the same period in the prior year.)